1. Field of the Invention
The present invention relates to a pump apparatus used to aspirate a patient""s gastro-intestinal tract and/or to deliver nutrients, fluids, medication and/or aspirate into a patient""s gastro-intestinal tract, preferably in conjunction with a combination feeding and aspiration tube. More specifically, this invention concerns a method and apparatus for use in cyclically or simultaneously aspirating, monitoring, and safely delivering nutrients, fluids, medications and/or aspirate into the gastro-intestinal tract as part of aspiration and feeding processes, permanently removing only potentially deleterious, physiologically excessive fluids.
2. Description of the Prior Art
Nutrients, fluids, medications and/or aspirate (collectively referred to as xe2x80x9cfeedingsxe2x80x9d) often are introduced directly into a patient""s gastro-intestinal tract via a feeding tube. This situation is discussed more fully in U.S. patent Application entitled xe2x80x9cSingle Lumen Gastro-Intestinal Feeding-Decompression Tubexe2x80x9d, filed herewith.
In many cases, a patient""s intestine is not operating fully, limiting the amount of nutrition the patient may receive. However, adequate nutrition is obviously a critical part of anyone""s health and is necessary to provide optimum recovery for a patient. It is thus desirable to deliver as much nutrition to a patient as can be absorbed safely by the patient""s impaired gastro-intestinal tract.
Unfortunately, it is not desirable simply to deliver a maximum amount of nutrition into a patient""s intestine. The reason for this is that overfeeding, which is delivering feedings at a rate exceeding the ability of the patient""s gastro-intestinal tract to absorb its own secretions plus the added nutrition, itself presents serious hazards to a patient. Overfeeding a patient leads to an accumulation of fluid, which distends the intestine. This intestinal distension can lead to fatal circulatory changes. More commonly, complications from overfeeding include the temporary further impairment of intestinal function, with nausea and vomiting, which at a minimum causes discomfort and delays recovery. Accordingly, it is desirable to limit delivery to avoid overfeeding, while at the same time delivering into the impaired intestine the maximum nutrition that can be absorbed safely.
Further complicating the feeding of patients via feeding tube is the fact that the body of its own accord produces considerable digestive secretions on a regular basis. In a healthy person, all of these digestive secretions, starting with saliva, are re-absorbed by the intestine, leading to no net change in bodily fluids. During a patient""s recovery from surgery or illness, the creation of digestive secretions is typically unaffected. Unfortunately, a patient""s gastro-intestinal function may be impaired considerably during recovery, so that the re-absorption of digestive secretions may not fully occur. Thus, nutrition delivered to the intestine may be competing with digestive secretions for absorption by the intestine. Furthermore, the presence of a feeding tube induces swallowing by a patient, which introduces additional air into the gastrointestinal tract. Swallowed air further compromises absorption. Meanwhile, it is not desirable to simply remove digestive secretions from a patient""s system, as this will dehydrate the patient. For this reason, feedings should be delivered to the patient in a way that accounts for any possible excess of digestive secretions, without dehydrating the patient, while also minimizing the presence of air.
Previously, a feeding tube might be aspirated manually to xe2x80x9ccheck for residualxe2x80x9d as a safety measure. In this process, feeding is interrupted and that portion of the patient""s gastro-intestinal tract is manually aspirated via the feeding tube. This xe2x80x9cresidualxe2x80x9d volume is measured and compared with an expected volume for an individual with normal gastro-intestinal function to determine whether the feeding rate should be maintained, increased, or reduced. The aspirate is either re-introduced or discarded. However, the check for residual process is labor intensive and, therefore, seldom used. Also, the check for residual process can, as a practical matter, be performed only a few times per day, which does not monitor gastro-intestinal function as closely as desired when directly feeding into the intestine.
As a step towards resolving these feeding difficulties, the inventor named herein has conceived of a single lumen gastro-intestinal feeding-decompression tube for use in delivering nutrition to a patient""s intestine and in net fashion removing all air and any excess liquids that are present in the intestine. This feeding tube is disclosed more fully in a U.S. patent application entitled xe2x80x9cSingle Lumen Gastro-Intestinal Feeding-Decompression Tubexe2x80x9d, filed simultaneously herewith. This application focuses upon a method and a pump control apparatus for use with the method for cyclically or simultaneously aspirating, monitoring, and delivering nutrition into the gastro-intestinal tract as part of aspiration and feeding processes. The pump control apparatus in accordance with the present invention may be used in conjunction with the applicant""s single lumen gastro-intestinal Feeding-decompression tube, as well as other feeding tubes that may be used in the simultaneous delivery of nutrition and aspiration of a patient""s gastro-intestinal tract. An alternative embodiment of the present invention provides simultaneous feeding and aspiration of the gastro-intestinal tract with separate feeding and aspiration tubes.
The present invention comprises a method and pump control assembly for use in alternating the delivery of nutrition to a patient""s gastro-intestinal tract and aspirating air and/or excess fluid from the gastro-intestinal tract. In its preferred embodiment, the pump assembly includes a relatively dense ball and a detector to sense the position of the ball. The position of the ball controls the operation of the pump. The relatively dense ball is lifted while material is being aspirated from the gastro-intestinal tract, but drops when the flow of aspirate stops. When the ball drops, the aspiration cycle is terminated and a feeding cycle begins.
In its broader sense, the pump control apparatus comprises a flow detector that controls the delivery of nutrition to and aspiration from a patient""s gastro-intestinal tract based upon the amount of aspirate flow obtained from a patient""s gastro-intestinal tract. Aspiration continues until aspirate flow ceases. After the aspirate flow ceases, a feeding cycle may commence. After the feeding cycle, the aspiration may resume.
The invention further comprises a method of delivering nutrition to a patient""s gastro-intestinal tract and aspirating the gastro-intestinal tract so as to obtain maximum nutritional absorption by the gastro-intestinal tract without the risk of overfeeding.